Research indicates that compared to those with other blood types, those in the type A blood group had a higher risk of having a stroke before the age of 60.
The wide range of substances that are visible on the surface of our red blood cells is referred to as blood kinds. Those with the names A and B are among the most well-known; they can be found as AB, separately as A or B, or absent altogether as O.
Subtle differences resulting from gene mutations can be seen even among these primary blood types.
Researchers studying genomics found a direct correlation between early onset stroke and the A1 subgroup gene in a study that was published in 2022.
Data from 48 genetic studies, comprising around 17,000 stroke victims and over 600,000 control subjects without a stroke, were combined by researchers. Every participant ranged in age from 18 to 59.
Two regions were found to be highly connected with an early risk of stroke after a genome-wide investigation. One aligned with the location of blood type genes.
In contrast to a population of persons with various blood types, those whose genome coded for a variant of the A group had a 16 percent increased likelihood of having a stroke before the age of 60, according to a second investigation of particular blood-type genes.
The risk was 12% lower for people who carried the group O1 gene.
Nonetheless, the researchers pointed out that there is no need for further caution or screening in this population because the risk of stroke in those with type A blood is negligible.
“We still don’t know why blood type A would confer a higher risk,” University of Maryland vascular neurologist Steven Kittner, senior author, said.
“But it likely has something to do with blood-clotting factors like platelets and cells that line the blood vessels as well as other circulating proteins, all of which play a role in the development of blood clots.”
Let’s put the research results in perspective, even if they may appear concerning at first—that blood type may alter an individual’s risk of an early stroke.
In the United States, less than 800,000 people have a stroke annually. Roughly three out of every four of these occurrences happen to adults 65 years of age and older, and the risk doubles every ten years beyond the age of 55.
Furthermore, the study’s participants were distributed across North America, Europe, Japan, Pakistan, and Australia, with just 35% of them having non-European ancestry. Clarifying the importance of the results might be aided by doing further research with a more varied population.
“We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk,” Kittner stated.
Comparing those who experienced a stroke prior to the age of 60 with those who experienced one later, revealed another important conclusion of the research.
The researchers examined a dataset consisting of around 25,000 individuals over 60 who were controls and 9,300 persons over 60 who had strokes.
They discovered that the type A blood group’s elevated risk of stroke vanished in the group of strokes with a late beginning, indicating that early-life strokes could operate through a distinct mechanism than later-life strokes.
According to the scientists, variables related to clot formation are more likely to cause strokes in younger individuals than atherosclerosis, or the accumulation of fatty deposits in the arteries.
The study also discovered that, regardless of age, those with type B blood had an approximately 11% increased risk of stroke compared to non-stroke controls.
Previous research indicates that coronary artery calcification, which inhibits blood flow, and heart attacks are linked to the “ABO locus,” a region of the genome that codes for blood type.
The A and B blood types’ genetic makeup has also been linked to a marginally increased risk of venous thrombosis, or blood clots in veins.
Neurology published this paper.
This story was originally published in September 2022.